mysql - Grails 和 MySQL 连接异常

Question

我有一个正在生产中的 grails 应用程序。今天早上我被告知服务器没有解析的事实。 Tomcat 不停地旋转。我研究了一下，看起来它与 MySQL 有关，导致连接在 8 小时不活动后超时。 I have found examples on stackoverflow有类似问题的人。但是，所有这些人都提到，如果他们再次访问服务器并刷新连接。对我来说，网站完全崩溃，Tomcat 不响应。听起来好像还有其他事情在起作用？

Tomcat 日志中的最后一个异常

2011-Aug-30 23:58:43,283 [TP-Processor19] org.hibernate.util.JDBCExceptionReporter
 ERROR The last packet successfully received from the server was 37,118,147 milliseconds ago.  The last packet sent successfully to the server was 37,122,138 milliseconds ago. \
is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing \
the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem.
2011-Aug-30 23:58:43,290 [TP-Processor19] org.codehaus.groovy.grails.web.errors.GrailsExceptionResolver
 ERROR Exception occurred when processing request: [GET] /picks/ncaafb
Stacktrace follows:
java.net.SocketException: Connection timed out
        at java.net.SocketOutputStream.socketWrite0(Native Method)
        at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)
        at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
        at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:65)
        at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:123)
        at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:3302)
        at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1940)
        at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2113)
        at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2568)
        at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2113)
        at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:2275)
  at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:2275)
        at org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:96)
        at org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:96)
        at sportsdb.Season.getCurrentNCAAFootballSeason(Season.groovy:93)
        at PicksController$_closure2.doCall(PicksController.groovy:60)
        at PicksController$_closure2.doCall(PicksController.groovy)
        at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:190)
        at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:291)
        at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:774)
        at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:703)
        at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:896)
        at java.lang.Thread.run(Thread.java:662)
2011-Aug-30 23:58:43,315 [TP-Processor19] org.hibernate.util.JDBCExceptionReporter
 ERROR Already closed.
2011-Aug-30 23:58:43,315 [TP-Processor19] org.hibernate.util.JDBCExceptionReporter
 ERROR Already closed.
2011-Aug-30 23:58:43,316 [TP-Processor19] org.codehaus.groovy.grails.web.servlet.GrailsDispatcherServlet
 ERROR HandlerInterceptor.afterCompletion threw exception
org.hibernate.exception.GenericJDBCException: Cannot release connection
        at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:190)
        at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:291)
        at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:774)
        at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:703)
        at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:896)
        at java.lang.Thread.run(Thread.java:662)
Caused by: java.sql.SQLException: Already closed.
        at org.apache.commons.dbcp.PoolableConnection.close(PoolableConnection.java:114)
        at org.apache.commons.dbcp.PoolingDataSource$PoolGuardConnectionWrapper.close(PoolingDataSource.java:191)
        at $Proxy7.close(Unknown Source)
        ... 6 more

我的计划是实现上面链接中提到的解决方案，但我想确保没有其他明显可疑的事情发生，因为我们得到的结果有些不同(他们的连接令人耳目一新，而我的则不然)。

Answer 1

如果您使用的是 Tomcat JNDI 数据源 look at some of the parameters you can set在数据源上，例如 testOnBorrow。如果验证失败，连接将从池中删除。测试连接会产生一些性能开销，但它应该可以解决这样的问题。如果您将 minIdle/maxIdle 设置得很高，这就可以解释为什么您在重新连接时继续遇到问题并为其他人修复它。